STC单片机实现printf

原创最新推荐文章于 2026-06-05 16:21:11 发布 5.9k 阅读 AI写同款

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关注

STC15单片机-串口打印printf重定向某些库函数的运行速度也比较慢，例如，memcpy()。microlib 是缺省 C 库的备选库，它指在需要装入到极少量内存中的深层嵌入式应用程序配合使用，这些应用程序不在操作系统中运行。网上文章许多都是说改写fputc函数，但我在这个程序中试了是不行的，会编译出错，定位到函数的FILE类型上，的时候，可以在keil软件的设置里，勾选Use MicroLIB选项，就可以使用fputc函数来实现重定向了。如果Cnt的类型是uint8_t的话，下面的格式化不变，还是%u，则串口输出的不是加1，而是加256了。阅读详情

AI摘要

本文介绍如何在STC8Axx单片机中使用printf函数发送串口数据，并结合外部中断实现特定事件（如按键按下）时的串口打印。首先展示了初始化串口的代码，然后演示了如何在外部中断INT0下降沿触发时，通过printf打印中断计数。在中断服务函数中，LED状态也会随着中断次数翻转，实现了中断和串口通信的结合。

《一》直接使用系统自带的printf函数:特别注意需要置位TI=1，否则是无法发送的，程序如下:

#include "STC8Axx.h"
#include <stdio.h>
#include <intrins.h>
void UartInit( void )           /* 115200bps@11.0592MHz */
{
	SCON	= 0x50;         /* 8位数据,可变波特率 */
	AUXR	|= 0x40;        /* 定时器1时钟为Fosc,即1T */
	AUXR	&= 0xFE;        /* 串口1选择定时器1为波特率发生器 */
	TMOD	&= 0x0F;        /* 设定定时器1为16位自动重装方式 */
	TL1	= 0xE8;         /* 设定定时初值 */
	TH1	= 0xFF;         /* 设定定时初值 */
	ET1	= 0;            /* 禁止定时器1中断 */
	TR1	= 1;            /* 启动定时器1 */
	ES	= 1;            /* 使能串口1中断 */
	TI	= 1;
}


void Delay100ms()               /* @11.0592MHz */
{
	unsigned char i, j, k;

	_nop_();
	_nop_();
	i	= 5;
	j	= 52;
	k	= 195;
	do
	{
		do
		{
			while ( --k )
				;
		}
		while ( --j );
	}
	while ( --i );
}


unsigned int cnt = 0;
void main()
{
	UartInit();
	EA = 1;
	printf( "printf Test!\r\n" );
	while ( 1 )
	{
		Delay100ms();
		Delay100ms();
		Delay100ms();
		printf( "BAUD = %d \r\n", (int) cnt );
		cnt++;
	}
}

STC8Axx.h

#ifndef __STC8F_H_
#define __STC8F_H_

/////////////////////////////////////////////////

//包含本头文件后,不用另外再包含"REG51.H"


//内核特殊功能寄存器
sfr ACC         =   0xe0;
sfr B           =   0xf0;
sfr PSW         =   0xd0;
sbit CY         =   PSW^7;
sbit AC         =   PSW^6;
sbit F0         =   PSW^5;
sbit RS1        =   PSW^4;
sbit RS0        =   PSW^3;
sbit OV         =   PSW^2;
sbit P          =   PSW^0;
sfr SP          =   0x81;
sfr DPL         =   0x82;
sfr DPH         =   0x83;
sfr TA          =   0xae;
sfr DPS         =   0xe3;
sfr DPL1        =   0xe4;
sfr DPH1        =   0xe5;


//I/O 口特殊功能寄存器
sfr P0          =   0x80;
sfr P1          =   0x90;
sfr P2          =   0xa0;
sfr P3          =   0xb0;
sfr P4          =   0xc0;
sfr P5          =   0xc8;
sfr P6          =   0xe8;
sfr P7          =   0xf8;
sfr P0M0        =   0x94;
sfr P0M1        =   0x93;
sfr P1M0        =   0x92;
sfr P1M1        =   0x91;
sfr P2M0        =   0x96;
sfr P2M1        =   0x95;
sfr P3M0        =   0xb2;
sfr P3M1        =   0xb1;
sfr P4M0        =   0xb4;
sfr P4M1        =   0xb3;
sfr P5M0        =   0xca;
sfr P5M1        =   0xc9;
sfr P6M0        =   0xcc;
sfr P6M1        =   0xcb;
sfr P7M0        =   0xe2;
sfr P7M1        =   0xe1;

sbit P00        =   P0^0;
sbit P01        =   P0^1;
sbit P02        =   P0^2;
sbit P03        =   P0^3;
sbit P04        =   P0^4;
sbit P05        =   P0^5;
sbit P06        =   P0^6;
sbit P07        =   P0^7;
sbit P10        =   P1^0;
sbit P11        =   P1^1;
sbit P12        =   P1^2;
sbit P13        =   P1^3;
sbit P14        =   P1^4;
sbit P15        =   P1^5;
sbit P16        =   P1^6;
sbit P17        =   P1^7;
sbit P20        =   P2^0;
sbit P21        =   P2^1;
sbit P22        =   P2^2;
sbit P23        =   P2^3;
sbit P24        =   P2^4;
sbit P25        =   P2^5;
sbit P26        =   P2^6;
sbit P27        =   P2^7;
sbit P30        =   P3^0;
sbit P31        =   P3^1;
sbit P32        =   P3^2;
sbit P33        =   P3^3;
sbit P34        =   P3^4;
sbit P35        =   P3^5;
sbit P36        =   P3^6;
sbit P37        =   P3^7;
sbit P40        =   P4^0;
sbit P41        =   P4^1;
sbit P42        =   P4^2;
sbit P43        =   P4^3;
sbit P44        =   P4^4;
sbit P45        =   P4^5;
sbit P46        =   P4^6;
sbit P47        =   P4^7;
sbit P50        =   P5^0;
sbit P51        =   P5^1;
sbit P52        =   P5^2;
sbit P53        =   P5^3;
sbit P54        =   P5^4;
sbit P55        =   P5^5;
sbit P56        =   P5^6;
sbit P57        =   P5^7;
sbit P60        =   P6^0;
sbit P61        =   P6^1;
sbit P62        =   P6^2;
sbit P63        =   P6^3;
sbit P64        =   P6^4;
sbit P65        =   P6^5;
sbit P66        =   P6^6;
sbit P67        =   P6^7;
sbit P70        =   P7^0;
sbit P71        =   P7^1;
sbit P72        =   P7^2;
sbit P73        =   P7^3;
sbit P74        =   P7^4;
sbit P75        =   P7^5;
sbit P76        =   P7^6;
sbit P77        =   P7^7;

//如下特殊功能寄存器位于扩展RAM区域
//访问这些寄存器,需先将P_SW2的BIT7设置为1,才可正常读写
#define P0PU        (*(unsigned char volatile xdata *)0xfe10)
#define P1PU        (*(unsigned char volatile xdata *)0xfe11)
#define P2PU        (*(unsigned char volatile xdata *)0xfe12)
#define P3PU        (*(unsigned char volatile xdata *)0xfe13)
#define P4PU        (*(unsigned char volatile xdata *)0xfe14)
#define P5PU        (*(unsigned char volatile xdata *)0xfe15)
#define P6PU        (*(unsigned char volatile xdata *)0xfe16)
#define P7PU        (*(unsigned char volatile xdata *)0xfe17)
#define P0NCS       (*(unsigned char volatile xdata *)0xfe18)
#define P1NCS       (*(unsigned char volatile xdata *)0xfe19)
#define P2NCS       (*(unsigned char volatile xdata *)0xfe1a)
#define P3NCS       (*(unsigned char volatile xdata *)0xfe1b)
#define P4NCS       (*(unsigned char volatile xdata *)0xfe1c)
#define P5NCS       (*(unsigned char volatile xdata *)0xfe1d)
#define P6NCS       (*(unsigned char volatile xdata *)0xfe1e)
#define P7NCS       (*(unsigned char volatile xdata *)0xfe1f)

//系统管理特殊功能寄存器
sfr PCON        =   0x87;
#define SMOD        0x80
#define SMOD0       0x40
#define LVDF        0x20
#define POF         0x10
#define GF1         0x08
#define GF0         0x04
#define PD          0x02
#define IDL         0x01
sfr AUXR        =   0x8e;
#define T0x12       0x80
#define T1x12       0x40
#define UART_M0x6   0x20
#define T2R         0x10
#define T2_CT       0x08
#define T2x12       0x04
#define EXTRAM      0x02
#define S1ST2       0x01
sfr AUXR2       =   0x97;
#define TXLNRX      0x10
sfr BUS_SPEED   =   0xa1;
sfr P_SW1       =   0xa2;
sfr P_SW2       =   0xba;
#define EAXFR       0x80
sfr VOCTRL      =   0xbb;
sfr RSTCFG      =   0xff;

//如下特殊功能寄存器位于扩展RAM区域
//访问这些寄存器,需先将P_SW2的BIT7设置为1,才可正常读写
#define CKSEL       (*(unsigned char volatile xdata *)0xfe00)
#define CLKDIV      (*(unsigned char volatile xdata *)0xfe01)
#define IRC24MCR    (*(unsigned char volatile xdata *)0xfe02)
#define XOSCCR      (*(unsigned char volatile xdata *)0xfe03)
#define IRC32KCR    (*(unsigned char volatile xdata *)0xfe04)

//中断特殊功能寄存器
sfr IE          =   0xa8;
sbit EA         =   IE^7;
sbit ELVD       =   IE^6;
sbit EADC       =   IE^5;
sbit ES         =   IE^4;
sbit ET1        =   IE^3;
sbit EX1        =   IE^2;
sbit ET0        =   IE^1;
sbit EX0        =   IE^0;
sfr IE2         =   0xaf;
#define ET4         0x40
#define ET3         0x20
#define ES4         0x10
#define ES3         0x08
#define ET2         0x04
#define ESPI        0x02
#define ES2         0x01
sfr IP          =   0xb8;
sbit PPCA       =   IP^7;
sbit PLVD       =   IP^6;
sbit PADC       =   IP^5;
sbit PS         =   IP^4;
sbit PT1        =   IP^3;
sbit PX1        =   IP^2;
sbit PT0        =   IP^1;
sbit PX0        =   IP^0;
sfr IP2         =   0xb5;
#define PI2C        0x40
#define PCMP        0x20
#define PX4         0x10
#define PPWMFD      0x08
#define PPWM        0x04
#define PSPI        0x02
#define PS2         0x01
sfr IPH         =   0xb7;
#define PPCAH       0x80
#define PLVDH       0x40
#define PADCH       0x20
#define PSH         0x10
#define PT1H        0x08
#define PX1H        0x04
#define PT0H        0x02
#define PX0H        0x01
sfr IP2H        =   0xb6;
#define PI2CH       0x40
#define PCMPH       0x20
#define PX4H        0x10
#define PPWMFDH     0x08
#define PPWMH       0x04
#define PSPIH       0x02
#define PS2H        0x01
sfr INTCLKO     =   0x8f;
#define EX4         0x40
#define EX3         0x20
#define EX2         0x10
#define T2CLKO      0x04
#define T1CLKO      0x02
#define T0CLKO      0x01
sfr AUXINTIF    =   0xef;
#define INT4IF      0x40
#define INT3IF      0x20
#define INT2IF      0x10
#define T4IF        0x04
#define T3IF        0x02
#define T2IF        0x01

//定时器特殊功能寄存器
sfr TCON        =   0x88;
sbit TF1        =   TCON^7;
sbit TR1        =   TCON^6;
sbit TF0        =   TCON^5;
sbit TR0        =   TCON^4;
sbit IE1        =   TCON^3;
sbit IT1        =   TCON^2;
sbit IE0        =   TCON^1;
sbit IT0        =   TCON^0;
sfr TMOD        =   0x89;
#define T1_GATE     0x80
#define T1_CT       0x40
#define T1_M1       0x20
#define T1_M0       0x10
#define T0_GATE     0x08
#define T0_CT       0x04
#define T0_M1       0x02
#define T0_M0       0x01
sfr TL0         =   0x8a;
sfr TL1         =   0x8b;
sfr TH0         =   0x8c;
sfr TH1         =   0x8d;
sfr T4T3M       =   0xd1;
#define T4R         0x80
#define T4_CT       0x40
#define T4x12       0x20
#define T4CLKO      0x10
#define T3R         0x08
#define T3_CT       0x04
#define T3x12       0x02
#define T3CLKO      0x01
sfr T4H         =   0xd2;
sfr T4L         =   0xd3;
sfr T3H         =   0xd4;
sfr T3L         =   0xd5;
sfr T2H         =   0xd6;
sfr T2L         =   0xd7;
sfr TH4         =   0xd2;
sfr TL4         =   0xd3;
sfr TH3         =   0xd4;
sfr TL3         =   0xd5;
sfr TH2         =   0xd6;
sfr TL2         =   0xd7;
sfr WKTCL       =   0xaa;
sfr WKTCH       =   0xab;
#define WKTEN       0x80
sfr WDT_CONTR   =   0xc1;
#define WDT_FLAG    0x80
#define EN_WDT      0x20
#define CLR_WDT     0x10
#define IDL_WDT     0x08

//串行口特殊功能寄存器
sfr SCON        =   0x98;
sbit SM0        =   SCON^7;
sbit SM1        =   SCON^6;
sbit SM2        =   SCON^5;
sbit REN        =   SCON^4;
sbit TB8        =   SCON^3;
sbit RB8        =   SCON^2;
sbit TI         =   SCON^1;
sbit RI         =   SCON^0;
sfr SBUF        =   0x99;
sfr S2CON       =   0x9a;
#define S2SM0       0x80
#define S2ST4       0x40
#define S2SM2       0x20
#define S2REN       0x10
#define S2TB8       0x08
#define S2RB8       0x04
#define S2TI        0x02
#define S2RI        0x01
sfr S2BUF       =   0x9b;
sfr S3CON       =   0xac;
#define S3SM0       0x80
#define S3ST4       0x40
#define S3SM2       0x20
#define S3REN       0x10
#define S3TB8       0x08
#define S3RB8       0x04
#define S3TI        0x02
#define S3RI        0x01
sfr S3BUF       =   0xad;
sfr S4CON       =   0x84;
#define S4SM0       0x80
#define S4ST4       0x40
#define S4SM2       0x20
#define S4REN       0x10
#define S4TB8       0x08
#define S4RB8       0x04
#define S4TI        0x02
#define S4RI        0x01
sfr S4BUF       =   0x85;
sfr SADDR       =   0xa9;
sfr SADEN       =   0xb9;

//ADC 特殊功能寄存器
sfr ADC_CONTR   =   0xbc;
#define ADC_POWER   0x80
#define ADC_START   0x40
#define ADC_FLAG    0x20
sfr ADC_RES     =   0xbd;
sfr ADC_RESL    =   0xbe;
sfr ADCCFG      =   0xde;
#define ADC_RESFMT  0x20

//SPI 特殊功能寄存器
sfr SPSTAT      =   0xcd;
#define SPIF        0x80
#define WCOL        0x40
sfr SPCTL       =   0xce;
#define SSIG        0x80
#define SPEN        0x40
#define DORD        0x20
#define MSTR        0x10
#define CPOL        0x08
#define CPHA        0x04
sfr SPDAT       =   0xcf;

//IAP/ISP 特殊功能寄存器
sfr IAP_DATA    =   0xc2;
sfr IAP_ADDRH   =   0xc3;
sfr IAP_ADDRL   =   0xc4;
sfr IAP_CMD     =   0xc5;
#define IAP_IDL     0x00
#define IAP_READ    0x01
#define IAP_WRITE   0x02
#define IAP_ERASE   0x03
sfr IAP_TRIG    =   0xc6;
sfr IAP_CONTR   =   0xc7;
#define IAPEN       0x80
#define SWBS        0x40
#define SWRST       0x20
#define CMD_FAIL    0x10
sfr ISP_DATA    =   0xc2;
sfr ISP_ADDRH   =   0xc3;
sfr ISP_ADDRL   =   0xc4;
sfr ISP_CMD     =   0xc5;
sfr ISP_TRIG    =   0xc6;
sfr ISP_CONTR   =   0xc7;

//比较器特殊功能寄存器
sfr CMPCR1      =   0xe6;
#define CMPEN       0x80
#define CMPIF       0x40
#define PIE         0x20
#define NIE         0x10
#define PIS         0x08
#define NIS         0x04
#define CMPOE       0x02
#define CMPRES      0x01
sfr CMPCR2      =   0xe7;
#define INVCMPO     0x80
#define DISFLT      0x40

//PCA/PWM 特殊功能寄存器
sfr CCON        =   0xd8;
sbit CF         =   CCON^7;
sbit CR         =   CCON^6;
sbit CCF3       =   CCON^3;
sbit CCF2       =   CCON^2;
sbit CCF1       =   CCON^1;
sbit CCF0       =   CCON^0;
sfr CMOD        =   0xd9;
#define CIDL        0x80
#define ECF         0x01
sfr CL          =   0xe9;
sfr CH          =   0xf9;
sfr CCAPM0      =   0xda;
#define ECOM0       0x40
#define CCAPP0      0x20
#define CCAPN0      0x10
#define MAT0        0x08
#define TOG0        0x04
#define PWM0        0x02
#define ECCF0       0x01
sfr CCAPM1      =   0xdb;
#define ECOM1       0x40
#define CCAPP1      0x20
#define CCAPN1      0x10
#define MAT1        0x08
#define TOG1        0x04
#define PWM1        0x02
#define ECCF1       0x01
sfr CCAPM2      =   0xdc;
#define ECOM2       0x40
#define CCAPP2      0x20
#define CCAPN2      0x10
#define MAT2        0x08
#define TOG2        0x04
#define PWM2        0x02
#define ECCF2       0x01
sfr CCAPM3      =   0xdd;
#define ECOM3       0x40
#define CCAPP3      0x20
#define CCAPN3      0x10
#define MAT3        0x08
#define TOG3        0x04
#define PWM3        0x02
#define ECCF3       0x01
sfr CCAP0L      =   0xea;
sfr CCAP1L      =   0xeb;
sfr CCAP2L      =   0xec;
sfr CCAP3L      =   0xed;
sfr CCAP0H      =   0xfa;
sfr CCAP1H      =   0xfb;
sfr CCAP2H      =   0xfc;
sfr CCAP3H      =   0xfd;
sfr PCA_PWM0    =   0xf2;
sfr PCA_PWM1    =   0xf3;
sfr PCA_PWM2    =   0xf4;
sfr PCA_PWM3    =   0xf5;

//增强型PWM波形发生器特殊功能寄存器
sfr PWMCFG      =   0xf1;
#define CBIF        0x80
#define ETADC       0x40
sfr PWMIF       =   0xf6;
#define C7IF        0x80
#define C6IF        0x40
#define C5IF        0x20
#define C4IF        0x10
#define C3IF        0x08
#define C2IF        0x04
#define C1IF        0x02
#define C0IF        0x01
sfr PWMFDCR     =   0xf7;
#define INVCMP      0x80
#define INVIO       0x40
#define ENFD        0x20
#define FLTFLIO     0x10
#define EFDI        0x08
#define FDCMP       0x04
#define FDIO        0x02
#define FDIF        0x01
sfr PWMCR       =   0xfe;
#define ENPWM       0x80
#define ECBI        0x40

//如下特殊功能寄存器位于扩展RAM区域
//访问这些寄存器,需先将P_SW2的BIT7设置为1,才可正常读写
#define PWMC        (*(unsigned int  volatile xdata *)0xfff0)
#define PWMCH       (*(unsigned char volatile xdata *)0xfff0)
#define PWMCL       (*(unsigned char volatile xdata *)0xfff1)
#define PWMCKS      (*(unsigned char volatile xdata *)0xfff2)
#define TADCP       (*(unsigned char volatile xdata *)0xfff3)
#define TADCPH      (*(unsigned char volatile xdata *)0xfff3)
#define TADCPL      (*(unsigned char volatile xdata *)0xfff4)
#define PWM0T1      (*(unsigned int  volatile xdata *)0xff00)
#define PWM0T1H     (*(unsigned char volatile xdata *)0xff00)
#define PWM0T1L     (*(unsigned char volatile xdata *)0xff01)
#define PWM0T2      (*(unsigned int  volatile xdata *)0xff02)
#define PWM0T2H     (*(unsigned char volatile xdata *)0xff02)
#define PWM0T2L     (*(unsigned char volatile xdata *)0xff03)
#define PWM0CR      (*(unsigned char volatile xdata *)0xff04)
#define PWM0HLD     (*(unsigned char volatile xdata *)0xff05)
#define PWM1T1      (*(unsigned int  volatile xdata *)0xff10)
#define PWM1T1H     (*(unsigned char volatile xdata *)0xff10)
#define PWM1T1L     (*(unsigned char volatile xdata *)0xff11)
#define PWM1T2      (*(unsigned int  volatile xdata *)0xff12)
#define PWM1T2H     (*(unsigned char volatile xdata *)0xff12)
#define PWM1T2L     (*(unsigned char volatile xdata *)0xff13)
#define PWM1CR      (*(unsigned char volatile xdata *)0xff14)
#define PWM1HLD     (*(unsigned char volatile xdata *)0xff15)
#define PWM2T1      (*(unsigned int  volatile xdata *)0xff20)
#define PWM2T1H     (*(unsigned char volatile xdata *)0xff20)
#define PWM2T1L     (*(unsigned char volatile xdata *)0xff21)
#define PWM2T2      (*(unsigned int  volatile xdata *)0xff22)
#define PWM2T2H     (*(unsigned char volatile xdata *)0xff22)
#define PWM2T2L     (*(unsigned char volatile xdata *)0xff23)
#define PWM2CR      (*(unsigned char volatile xdata *)0xff24)
#define PWM2HLD     (*(unsigned char volatile xdata *)0xff25)
#define PWM3T1      (*(unsigned int  volatile xdata *)0xff30)
#define PWM3T1H     (*(unsigned char volatile xdata *)0xff30)
#define PWM3T1L     (*(unsigned char volatile xdata *)0xff31)
#define PWM3T2      (*(unsigned int  volatile xdata *)0xff32)
#define PWM3T2H     (*(unsigned char volatile xdata *)0xff32)
#define PWM3T2L     (*(unsigned char volatile xdata *)0xff33)
#define PWM3CR      (*(unsigned char volatile xdata *)0xff34)
#define PWM3HLD     (*(unsigned char volatile xdata *)0xff35)
#define PWM4T1      (*(unsigned int  volatile xdata *)0xff40)
#define PWM4T1H     (*(unsigned char volatile xdata *)0xff40)
#define PWM4T1L     (*(unsigned char volatile xdata *)0xff41)
#define PWM4T2      (*(unsigned int  volatile xdata *)0xff42)
#define PWM4T2H     (*(unsigned char volatile xdata *)0xff42)
#define PWM4T2L     (*(unsigned char volatile xdata *)0xff43)
#define PWM4CR      (*(unsigned char volatile xdata *)0xff44)
#define PWM4HLD     (*(unsigned char volatile xdata *)0xff45)
#define PWM5T1      (*(unsigned int  volatile xdata *)0xff50)
#define PWM5T1H     (*(unsigned char volatile xdata *)0xff50)
#define PWM5T1L     (*(unsigned char volatile xdata *)0xff51)
#define PWM5T2      (*(unsigned int  volatile xdata *)0xff52)
#define PWM5T2H     (*(unsigned char volatile xdata *)0xff52)
#define PWM5T2L     (*(unsigned char volatile xdata *)0xff53)
#define PWM5CR      (*(unsigned char volatile xdata *)0xff54)
#define PWM5HLD     (*(unsigned char volatile xdata *)0xff55)
#define PWM6T1      (*(unsigned int  volatile xdata *)0xff60)
#define PWM6T1H     (*(unsigned char volatile xdata *)0xff60)
#define PWM6T1L     (*(unsigned char volatile xdata *)0xff61)
#define PWM6T2      (*(unsigned int  volatile xdata *)0xff62)
#define PWM6T2H     (*(unsigned char volatile xdata *)0xff62)
#define PWM6T2L     (*(unsigned char volatile xdata *)0xff63)
#define PWM6CR      (*(unsigned char volatile xdata *)0xff64)
#define PWM6HLD     (*(unsigned char volatile xdata *)0xff65)
#define PWM7T1      (*(unsigned int  volatile xdata *)0xff70)
#define PWM7T1H     (*(unsigned char volatile xdata *)0xff70)
#define PWM7T1L     (*(unsigned char volatile xdata *)0xff71)
#define PWM7T2      (*(unsigned int  volatile xdata *)0xff72)
#define PWM7T2H     (*(unsigned char volatile xdata *)0xff72)
#define PWM7T2L     (*(unsigned char volatile xdata *)0xff73)
#define PWM7CR      (*(unsigned char volatile xdata *)0xff74)
#define PWM7HLD     (*(unsigned char volatile xdata *)0xff75)

//I2C特殊功能寄存器
//如下特殊功能寄存器位于扩展RAM区域
//访问这些寄存器,需先将P_SW2的BIT7设置为1,才可正常读写
#define I2CCFG      (*(unsigned char volatile xdata *)0xfe80)
#define ENI2C       0x80
#define MSSL        0x40
#define I2CMSCR     (*(unsigned char volatile xdata *)0xfe81)
#define EMSI        0x80
#define I2CMSST     (*(unsigned char volatile xdata *)0xfe82)
#define MSBUSY      0x80
#define MSIF        0x40
#define MSACKI      0x02
#define MSACKO      0x01
#define I2CSLCR     (*(unsigned char volatile xdata *)0xfe83)
#define ESTAI       0x40
#define ERXI        0x20
#define ETXI        0x10
#define ESTOI       0x08
#define SLRST       0x01
#define I2CSLST     (*(unsigned char volatile xdata *)0xfe84)
#define SLBUSY      0x80
#define STAIF       0x40
#define RXIF        0x20
#define TXIF        0x10
#define STOIF       0x08
#define TXING       0x04
#define SLACKI      0x02
#define SLACKO      0x01
#define I2CSLADR    (*(unsigned char volatile xdata *)0xfe85)
#define I2CTXD      (*(unsigned char volatile xdata *)0xfe86)
#define I2CRXD      (*(unsigned char volatile xdata *)0xfe87)

/////////////////////////////////////////////////

#endif

然而你想结合外部中断同时使用上述printf语句，是不能达到预期的效果。具体来说，用消抖按键连接P3.2即INT0,希望每次按键按下时串口打印“INT0 counter= ”.

上述语句是不能响应外部中断的。经查是不应该启用TI=0；语句，同时添加串口发送字节语句，完整代码如下：

#include "STC8Axx.h"
#include <stdio.h>
#include <intrins.h>
void UartInit( void )           /* 115200bps@11.0592MHz */
{
	SCON	= 0x50;         /* 8位数据,可变波特率 */
	AUXR	|= 0x40;        /* 定时器1时钟为Fosc,即1T */
	AUXR	&= 0xFE;        /* 串口1选择定时器1为波特率发生器 */
	TMOD	&= 0x0F;        /* 设定定时器1为16位自动重装方式 */
	TL1	= 0xE8;         /* 设定定时初值 */
	TH1	= 0xFF;         /* 设定定时初值 */
	ET1	= 0;            /* 禁止定时器1中断 */
	TR1	= 1;            /* 启动定时器1 */
	ES	= 1;            /* 使能串口1中断 */
	/*	TI=1; */
}


void UART_SendChar( unsigned char Dat )
{
	SBUF = Dat;
	while ( !TI )
		;
	TI = 0;
}


char putchar( char c )
{
	UART_SendChar( c );
	return(c);
}


void Delay100ms()         /* @11.0592MHz */
{
	unsigned char i, j, k;

	_nop_();
	_nop_();
	i	= 5;
	j	= 52;
	k	= 195;
	do
	{
		do
		{
			while ( --k )
				;
		}
		while ( --j );
	}
	while ( --i );
}


unsigned int	cnt	= 0;
unsigned int	INTcnt	= 0;
unsigned char	FLAG	= 0;
sbit		LED	= P2 ^ 1;
void main()
{
	UartInit();
	IT0	= 1;    /* 使能INT0下降沿中断 */
	EX0	= 1;    /* 使能INT0中断 */
	EA	= 1;

	printf( "STC8 UART1 Printf Test!\r\n" );
	while ( 1 )
	{
		Delay100ms();
		Delay100ms();
		Delay100ms();
		printf( "BAUD = %d \r\n", (int) cnt );
		cnt++;
		if ( FLAG == 1 )
		{
			INTcnt++;
			printf( "INT0 counts=%d\r\n", (int) INTcnt );
			FLAG = 0;
		}
	}
}


void INT0_Isr() interrupt 0
{
	FLAG	= 1;
	LED	= !LED;
}